Problem statement

One of the issues we hear about the most is how to reclaim disk space used by docker. I suggest to start small by adding a way to understand and visualize how disk space is used, before building additional support for managing this data.

Possible solution

One simple idea would by to provide the equivalent of a docker df, which would show you:

• Space used by images (tagged versus untagged?)
• Space used by containers (running versus stopped?)
• Space used by volumes (referenced versus dangling?)

A natural evolution of that would be to offer one-liners to reclaim space consumed by unused images, dangling volumes, or stopped containers.

Ping @docker/core-maintainers: I'm interested to hear what you think!